tdcs for auditory hallucinations in schizophrenia

Conditions: Schizophrenia

Summary: the purpose of the present research is to test a potential new treatment for auditory verbal hallucinations in schizophrenia that uses transcranial direct current stimulation (tdcs), a neurostimulation technique that passes an extremely weak electric current through the brain. during the treatment, two electrodes are positioned on the scalp above regions of the brain implicated in abnormal cortical activity associated with auditory verbal hallucinations in schizophrenia. due to the directional flow of current, one electrode, termed "cathodal",inhibits cortical activity, and the other, termed "anodal", increases cortical activity. these electrodes will be placed such that cathodal stimulation is applied to an area associated with hyperactivity and anodal stimulation to an area associated with hypoactivity. one preliminary study has revealed that this form of neurostimulation can alleviate auditory verbal hallucination symptoms both immediately following five days of treatment and up to three months after the final treatment. the goal of this study is to replicate these effects and explore the mechanisms that may underpin them.

90 patients with persistent auditory verbal hallucinations will be recruited to this study. each individual will participate in behavioral assessments lasting up to 3 hours each and will then be randomized to receive a series of active vs. sham tdcs treatments. for active treatment, patients will have the inhibitory (cathodal) tdcs electrode placed over left auditory cortex relative to an anodal placed over frontal cortex on the right side. tdcs treatments will take place for 20 min per day for 5 consecutive days. for sham, procedures will be similar except that sham (inactive) tdcs treatment will be used. assessment batteries will then be repeated following completion of treatment and at 1 and 3 mo following treatment. in addition, patients will be offered the possibility to participate in a concurrent magnetic resonance imaging (mri) study aimed at evaluating the effects of tdcs on activation of auditory cortex during an auditory discrimination task as well as on other imaging parameters related to resting brain activity and metabolism. patients who agree to participate in this mri study will be scanned before and after active or sham tdcs. in addition, 5-15 schizophrenia patients will complete a week of high-density, e.g., "high-definition" tdcs (hd-tdcs) open label. in addition to hallucinating patients, we will recruit up to 20 healthy controls and 20 non-hallucinating patients, who will have similar assessments to the patients, but will not receive tdcs. overall, the investigators hypothesize that tdcs treatment will lead to reduction in hallucinations, improvement in auditory function, and change in eeg and mri measurements so that patients more closely resemble healthy volunteers and non-hallucinating patients.

Eligibility criteria:
inclusion criteria: * age between 18-55 * structured clinical interview for dsm disorders (scid) primary diagnosis of dsm-iv (diagnostic and statistical manual of mental disorders-version iv) schizophrenia or schizoaffective disorder * persistent auditory verbal hallucinations * right handed * stable antipsychotic medication for \> 4 weeks * normal hearing * if female and not infertile, must agree to use one of the following forms of contraception for the duration of study participation: systemic hormonal treatment, an interuterine device (iud) which was implanted at least 2 months prior to screening, or "double-barrier" contraception * willing/capacity to provide informed consent exclusion criteria: * substance dependence or abuse (excluding nicotine) in the past 90 days * current significant laboratory abnormality * history of seizure, epilepsy in self or fist degree relatives, stroke, brain surgery, head injury with loss of consciousness \> 1 hour or clear cognitive sequelae, intracranial metal implants, known structural brain lesion, devices that may be affected by transcranial direct current stimulation (tdcs) (pacemaker, medication pump, cochlear implant, implanted brain stimulator) * frequent and persistent migraines * history of adverse reaction to neurostimulation or open skin wounds that would preclude safe placement of tdcs electrodes * participation in study of investigational medication/device within 4 weeks * current use of medications known to lower seizure threshold (lithium, serotonergic or tricyclic antidepressants) * if female, pregnant or breast feeding at the time of screening * for mri study only: claustrophobia or metal implants or paramagnetic objects contained within the body which may interfere with the mri scan, as determined according to the guidelines set forth in the following reference book: "guide to mr procedures and metallic objects" shellock, phd, lippincott-raven press, ny 1998

Keywords: schizophrenia